By now, you are probably aware that Mumford & Sons have finally finished the follow-up to their breakout Sigh No More album, and that it will hit stores on September 25. But unless you're familiar with international maritime signal flags, there's a pretty good chance you don't know what that new album is going to be called.

Or at least what we think it's going to be called. Because on Wednesday, Mumford posted a new teaser video on their official site, one that shows brief flashes of a rather raging old-tyme party (Ragtime! Some dude breathing fire! A horse!), then ends with a brief scene of the Mumford guys sitting amid the subsequent aftermath, suitcases and bowler hats strewn about. As the clip fades to black, fans are shown a series of five signal flags that spell out the word "Babel."

It's not clear whether "Babel" refers to the title of the upcoming album, or is perhaps the name of its first single, though clearly, Mumford are up to something (eagle-eyed fans have also noticed that a second set of flags featured in the video spell out the word "Tour"), and they're going about it in an appropriately anachronistic manner. For those not up on the Old Testament, "Babel" is the Hebrew name for Babylon, the location where a massive tower was set to be built, only to be halted when God "confounded ... the language of all the earth."

A spokesperson for Mumford told MTV News there was no confirmation on the title of the band's new album (or new single). Mumford & Sons also announced that they'd be expanding their U.S. tour, which previously had only included four stops on their so-called "Gentlemen of the Road" mini-fest. The new dates kick off August 1 in Hoboken, New Jersey, and run until September 1, with an appearance at the Jazz Aspen Snowmass Festival in Colorado.